I was thinking the same thing only with rubber. Kevlar is 1000 times better though.

You either air down for flotation (sand) or conformability (rock crawling). In either case you need to air back up on the highway because a tire with low air pressure heats up more and is more prone to a failure at highway speed. Airing down will also put the sidewall closer to the ground and in a better place to get punctured. You can plug tread holes (within reason) but sidewalls are a completely different animal.

Bill

I know not how to answer your specific question, concerning smaller but sharp stones.

But on a somewhat related topic, -I've read in books concerning Desert Vehicular travel, (Sahara Overland by Chris Scott / Trailblazer has got to be one of the Very Best!), -that a Washboard Effect develops on typical unpaved Desert Trails. This from the repeated driving which takes place on them, over time. Its something that you've got to be Aware of, -and Watch Out for / Adjust to.